The present invention relates to a screw for dental implants. This screw is of the type used in certain dental surgery techniques and is normally anchored in the maxillary bones and serves as a basis for holding the dental prostheses fitted subsequently. In other words, in the majority of surgical techniques for the fitting of dental prostheses, these screws are basic elements for the firm fitting of the artificial pieces replacing the diseased, faulty or deficient natural pieces.
As stated above, for several years dental surgery techniques have been known for allowing the fitting of dental prostheses by fixation or holding to anchoring members previously inserted in the bone tissue of the upper and lower maxillary bones or jawbones.
As disclosed in the German patent No. P 30 34 086.4-35, the anchoring device for the dental implant is a prismatic body which is hard to fit and which, because of its geometrical form, does not ensure a sufficiently high degree of firmness. Furthermore, there are certain difficulties for fitting this anchorage in the maxillary bone due precisely to its longer axis which is to be placed transverse relative to the axis of the dental piece.
Spanish utility model No. 272,292 discloses a screw for dental implants, the main body of which is smooth at the bottom end thereof, providing for the possibility of rotation and consequently hindering the integration of the constituent material thereof in the bone. Also, the screw disclosed in the above embodiment has the upper end thereof void of external reliefs for facilitating attachment and holding of the dental prosthesis.
Spanish utility model No. 279,140 describes an anchoring element for dental implants, similar to a screw, which comprises two separate parts and which also requires the additional use of O-rings to provide a firm attachment of the dental prosthesis.
All these embodiments and the others also known and generally used up to date may, in general terms, be included in two classes: (a) they have a simple geometrical form having the drawback of not allowing comfortable effective manageability during the implantation operations and, furthermore, they do not ensure a high degree of firm permanence in their location; and, (b) they have a complex structure, generally adapted to ensure good anchorage of both the screw in the maxillary bone and of the prosthesis to the screw itself, but they require a difficult, long, delicate assembly operation, precisely because of the complex forms and structures thereof.
Relatively low security levels of these known screws frequently lead the dental surgeons to allow a very extended period of time to elapse between the implantation of the anchoring screw and the subsequent fitting of the dental prosthesis. On many occasions this period is four, six and may even reach eight months.